This disclosure relates generally to light emitting diodes (LED) dice having wavelength conversion layers and to a method and system for fabricating light emitting diode (LED) dice with wavelength conversion layers having controlled color characteristics.
Light emitting diode (LED) dice have been developed that produce white light. In order to produce white light, a blue (LED) die can be used in combination with a wavelength conversion layer, such as a phosphor layer formed on the surface of the die. The electromagnetic radiation emitted by the blue (LED) die excites the atoms of the wavelength conversion layer, which converts some of the electromagnetic radiation in the blue wavelength spectral region to the yellow wavelength spectral region. The ratio of the blue to the yellow can be manipulated by the composition and geometry of the wavelength conversion layer, such that the output of the light emitting diode (LED) die appears to be white light.
In this type of light emitting diode (LED) die, the characteristics of the white light are determined by the electromagnetic radiation emitted by the LED die and by the wavelength conversion properties of the wavelength conversion layer. For example, the color characteristics of the white light depends upon the spectral distribution of electromagnetic radiation produced by the wavelength conversion layer. Any variations in the spectral distribution can vary the color characteristics resulting in an undesirable color balance and a faulty color rendition.
It is difficult to fabricate light emitting diode (LED) dice with consistent color balance because any variations in the fabrication process can change the output of the wavelength conversion layers. The present disclosure is directed to a method and system for fabricating light emitting diode (LED) dice with wavelength conversion layers having controlled color characteristics. Using the method and system light emitting diode (LED) dice can be fabricated to produce white light having a desired color temperature, color balance and spectral distribution.